How tiring is a north-to-south Vietnam tour - lots of early starts and internal flights?

We’re reasonably fit but a few itineraries pack in internal flights and 7am departures most days. We want to actually enjoy it, not just survive it. For anyone who’s done a guided Vietnam tour, how was the real day-to-day rhythm - manageable, or full-on?

Hi, I did the Hanoi to Cambodia tour last year, as a solo traveler I found it was very manageable, I was not with a group as intended, which seems to happen quite a lot. It was the discovering Indochina tour with Legend travel, it was well organised. There were two flights. One to Hoi an and one to Ho chi min city. There was a very long coach ride, and also a long fast boat trip to cambodia. The trip was called A Mekong Delta Adventure 17-Day. I would highly recommend it. Halong Bay is beautiful.